CN1872663A - Technique for preparing synthesis gas from coke oven gas - Google Patents

Abstract

The invention discloses a process for producing synthesis gas from coke oven gas. Specifically, organic membranes are used to separate and enrich methane and hydrogen in coke oven gas in a coking plant, and then the obtained methane-rich gas is produced by high-temperature carbon-loaded partial oxidation. Syngas with different _H2 /CO ratios were taken. The process enriches hydrogen up to 92% and methane up to 65%. The methane-enriched gas adopts high-temperature carbon-loaded partial oxidation to produce synthesis gas. The conversion rate of methane can reach 98%, and the yield of synthesis gas can reach 90%. H ₂ /CO ratio can be adjusted arbitrarily. The invention utilizes the coke oven gas discharged during the production process of the coking plant to effectively prepare synthesis gas, which not only utilizes energy, but also solves the problem of environmental pollution, and is a new practical coke oven gas production synthesis gas process.

Description

A coke oven gas-to-synthesis gas process

technical field

The invention relates to a method for producing synthesis gas from coke oven gas, in particular to a method for producing synthesis gas through high-temperature carbon-supported partial oxidation of coke oven gas with organic membrane separation to remove hydrogen and residual methane.

technical background

China is a big country of coke production. In 2004, China's coke production reached 209 million tons, accounting for 49% of the world's total coke production. However, coke oven gas cannot be effectively utilized, and about 29 billion to 30 billion Nm are emptied every year by "lighting sky lanterns". ^3. It is equivalent to twice the annual gas transmission volume of the country's West-to-East Gas Transmission, causing serious environmental pollution and waste of resources. At present, in the entire production chain from natural gas to downstream liquid products such as methanol and fuel oil, 60%~ 70% of the production cost is the production process of synthesis gas. In order to effectively utilize a large amount of coke oven gas resources and reduce the production cost of synthesis gas, this subject researches a process of producing synthesis gas from coke oven gas.

Contents of the invention

The invention utilizes coke oven gas discharged during the production process of a coking plant to produce synthesis gas to utilize energy and solve the problem of energy waste and environmental pollution, and aims to provide a process for producing synthesis gas from coke oven gas.

Based on the above problems and objectives, the present invention proposes a coke oven gas synthesis gas process, which is to use organic membranes to separate and enrich the methane and hydrogen in the coke oven gas after purification, and then convert the obtained methane-enriched gas to high-temperature carbon Partial oxidation to produce synthesis gas.

Wherein, the hydrogen-rich gas produced during the process can be used to adjust the ratio of H ₂ /CO in the synthesis gas.

Realize the concrete process step of the present invention as follows:

Firstly, after storing the coke oven gas, pressurize and keep the pressure at 2-4MPa, then purify at a flow rate of 0.1-100L/min, and freeze and crystallize the naphthalene in the coke oven gas, the freezing temperature is -15℃～-28℃, After filtration and adsorption, the naphthalene content in the coke oven gas is <30 mg/Nm ³ and the benzene content is <10 g/Nm ³ .

Secondly, the purified coke oven gas is sent to the organic membrane separator at a pressure of 0.1-1.4 MPa, and the separated hydrogen-rich gas is stored, and then the separated methane-rich gas is exchanged with the reacted gas, Send it to the methanator, the space velocity is 2-200min ^-1 , the ratio of methane-rich gas and oxygen is between 0.8-7, and the temperature is 800℃-1200℃ for another reaction, that is, the H ₂ /CO ratio is between 0.2 ~2 Adjustable syngas with methane conversion rate of 85%~98%.

The present invention is a coke oven gas synthesis gas process method, which effectively prepares synthesis gas by using the coke oven gas wasted in the production process of the coking plant by "lighting sky lanterns", which not only utilizes energy, but also solves the waste of resources problems, and more importantly, to solve the problem of environmental pollution. About 29 to 30 billion Nm ³ of coke oven gas is vented every year in China, which is equivalent to twice the annual gas transmission volume of the country’s West-to-East Gas Transmission Project, causing serious resource waste and environmental pollution. Therefore, this The invention has substantive features and significant progress, and also has great practical significance.

Compared with the prior art, the present invention adopts pressure swing adsorption or deep freezing to separate hydrogen in coal gas, and the present invention uses organic membrane to separate and has better economy than pressure swing adsorption and deep freezing methods. The existing technology of methane conversion to synthesis gas generally uses nickel-based and other composite catalysts for catalytic conversion (including steam reforming, carbon dioxide reforming or partial oxidation), while the present invention is carbon-supported partial oxidation conversion, which effectively utilizes a large amount of coking plant Coke powder resources also solve the environmental pollution problem of coke powder and increase the benefits of enterprises.

Description of drawings

Fig. 1 is a schematic diagram of the process flow of the present invention

In the figure: 1: gas cabinet 2: compressor 3: gas storage tank 4, 5, 6 and 7: purifier 8: membrane separator 9: heat exchanger 10: methane conversion reactor

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and implementation examples.

Example 1

The invention discloses a process for producing synthesis gas from coke oven gas. The raw materials used are recovered and purified coke oven gas, coke powder, oxygen, etc. in a coking plant; the auxiliary equipment used are refrigeration equipment, purifiers, three-way valves, and gas compressors. , gas storage tanks, membrane separators, fixed bed reactors, etc. In this method, organic membranes are used to separate and enrich methane and hydrogen in coke oven gas purified by general coking plants, and then the obtained methane-enriched gas is partially oxidized with fixed-bed high-temperature carbon to produce synthesis gas, and the obtained hydrogen-enriched gas is used for Adjust the _H2 /CO ratio in the syngas.

Concrete process implementation steps of the present invention are as follows:

As shown in Figure 1, the coke oven gas compressor 2 (model: ZW-0.2/1-30) with a volume of 3 to ⁵ m3 in the gas cabinet 1 of the coking plant is pumped into the gas storage tank 3 (gas storage tank: φ800mm , H=1500mm, can hold 3m ³ coal gas, the maximum pressure is 4MPa), keep the pressure of the gas storage tank 3 at 2-4MPa, then pass the gas in the gas storage tank 3 through the purifier 4, respectively with a flow rate of 0.1-100L/min 5, 6 and 7 four-stage purification, of which 4 is a freezer (freezer, the lowest temperature is -28°C, a purifier, size φ70mm, H=400mm), freezing naphthalene in crystalline gas, freezing temperature -15°C ~ -28°C . 5 is for glass wool to block the dust and part of the tar mist in the gas. 6 is the water in the silica gel adsorption gas. 7 is that the molecular sieve adsorbs benzene and other impurities in the gas, so that the naphthalene content in the gas is about <30mg/Nm ³ and the benzene content is <10g/Nm ³ . Then the purified coke oven gas enters the organic membrane separator 8 (membrane separator, model prism.) at an inlet pressure of 0.1-1.4MPa, the hydrogen-rich gas is connected to the hydrogen storage cabinet, and the methane-rich gas is partially emptied in the tee , the remaining gas enters heat exchanger 9 (snake tube heat exchanger, φ100×500mm) and enters methane reformer 10 after heat exchange (methane conversion reactor, corundum tube φ25×500mm, silicon carbon tube heating, platinum rhodium-platinum thermocouple temperature control.), the space velocity is 2-200min ^-1 , the ratio of methane-rich gas and oxygen is between 0.8-7, the temperature is 800℃-1200℃ for reaction, after the reaction, H ₂ /CO is between 0.2- 2, the methane conversion rate is between 85% and 98%, and the hydrogen in the hydrogen storage tank is added to the synthesis gas according to the use of the synthesis gas to adjust the H ₂ /CO ratio of the synthesis gas.

Main component and parameter in embodiment 1 are as follows:

The space velocity of the methane conversion reactor is 166.7min ^-1 , the ratio of methane-enriched gas and oxygen is 3:1, the tube is filled with coke powder with a particle size of 1-15mm, and the reaction temperature is 800°C. The coke oven gas enters the membrane separator and the inlet pressure is 0.2 MPa, the composition of outlet hydrogen-rich gas and methane-rich gas flow rate of 1:1 is shown in Table 1, and the gas composition is tested according to GB12205-90, the same below.

Table 1 Membrane separation effect at inlet pressure of 0.2MPa composition CO ₂ C _m H _n O ₂ CO CH ₄ H ₂ N ₂ hydrogen rich 3.4 1.0 0.6 2.0 13.0 84.9 0.1 methane-rich gas 1.6 4.2 1.2 11.4 64.2 0.4 17.0

The space velocity of the methane conversion reactor was 3.1min ^-1 , the ratio of methane-enriched gas and oxygen was 6.5:1, the tube was filled with coke powder with a particle size of 3-10mm, and the reaction temperature was 1200°C. The reaction results are shown in Table 2.

Table 2 Results of methane-enriched gas conversion composition CO ₂ C _m H _n O ₂ CO CH ₄ H ₂ N ₂ CH ₄ conversion H ₂ /CO after reaction 5.0 0.6 0.6 65 2.02 13.63 13.15 96.9% 0.21

Example 2

According to the processing method of embodiment 1, the main components and parameters of embodiment 2 are as follows:

The inlet pressure of the coke oven gas into the membrane separator is 0.8Mpa, and the outlet flow rate of hydrogen-rich gas and methane-rich gas is 1:1, as shown in Table 3.

Table 3 Membrane separation effect at inlet pressure of 0.8MPa CO ₂ C _m H _n O ₂ CO CH ₄ H ₂ N ₂ hydrogen rich 3.2 1.0 0.6 2.0 11.2 82.0 0.0 methane-rich gas 1.0 5.6 0.8 16 65.5 1.7 9.4

The space velocity of the methane conversion reactor was 2.46min ^-1 , the ratio of methane-enriched gas and oxygen was 4.9:1, the tube was filled with coke powder with a particle size of 3-10mm, and the reaction temperature was 1200°C. The reaction results are shown in Table 4.

Table 4 Results of methane-enriched gas conversion composition CO ₂ C _m H _n O ₂ CO CH ₄ H ₂ N ₂ CH ₄ conversion H ₂ /CO after reaction 6.6 0.2 1.6 55.2 7.74 21.46 7.2 88.2% 0.39 after reaction 5.2 4.4 1.4 32.2 7.94 50.65 -1.79 85.8% 1.57

Example 3

According to the processing method of embodiment 1, the main components and parameters of embodiment 3 are as follows:

The inlet pressure of the coke oven gas into the membrane separator is 1.3Mpa, and the outlet flow rate of hydrogen-rich gas and methane-rich gas is 1:1, as shown in Table 5.

Table 5 Membrane separation effect at inlet pressure of 1.3MPa CO ₂ C _m H _n O ₂ CO CH ₄ H ₂ N ₂ hydrogen rich 2.2 1.4 0.4 0.6 7.6 90.4 -2.6 methane-rich gas 1.2 5.4 1.4 13.6 55.9 16.7 5.6

The space velocity of the methane conversion reactor was 166.7min ^-1 , the ratio of methane-enriched gas and oxygen was 3:1, the tube was filled with coke powder with a particle size of 1~15mm, and the reaction temperature was 800°C. The reaction results are shown in Table 6.

Table 6 Results of methane-enriched gas conversion composition CO ₂ C _m H _n O ₂ CO CH ₄ H ₂ N ₂ CH ₄ conversion H ₂ /CO after reaction 5.2 4.4 1.4 32.2 7.94 50.65 -1.79 85.8% 1.57

Claims (3)

1. A coke oven gas synthesis gas process, characterized in that after the coke oven gas is purified, the organic membrane is used to separate and enrich methane and hydrogen, and then the high-temperature carbon-loaded partial oxidation of the gained methane-enriched gas is used to produce synthesis gas. 2. A coke oven gas synthesis gas process as claimed in claim 1, characterized in that the hydrogen-rich gas in the process can be used to adjust the ratio of _H2 /CO in the synthesis gas. 3. A coke oven gas synthesis gas process as claimed in claim 1, characterized in that the process steps are carried out in the following order: Firstly, after storing the coke oven gas, pressurize and keep the pressure at 2-4MPa, then purify at a flow rate of 0.1-100L/min, and freeze and crystallize the naphthalene in the coke oven gas, the freezing temperature is -15℃～-28℃, After filtration and adsorption, the naphthalene content in the coke oven gas is <30 mg/Nm ³ and the benzene content is <10 g/Nm ³ . Next, send the purified coke oven gas into the organic membrane separator (8) at a pressure of 0.1-1.4 MPa, store the separated hydrogen-rich gas, and exchange the separated methane-rich gas with the reacted gas. After heating, it is sent to the methanator (10), the space velocity is 2-200min ^-1 , the ratio of methane-rich gas to oxygen is 0.8-7, and the temperature is 800°C-1200°C for another reaction to obtain H ₂ The synthesis gas whose /CO ratio is adjustable between 0.2 and 2 has a methane conversion rate of 85% to 98%.

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